a) Field of the Invention
This invention relates to novel 4-oxo-3-quinolinecarboxylic acids, to methods for the preparation thereof, and compositions and methods for the use thereof as antibacterial agents.
b) Information Disclosure Statement
Antibacterially active 4-oxo-3-quinolinecarboxylic acids are known in the prior art which includes the following references.
Lesher and Carabateas U.S. Pat. No. 3,753,993, issued Aug. 21, 1973, discloses 7-(2,6-dimethyl -4-pyridinyl)-1-ethyl-1,4-dihydro-4-oxo-3-quinolinecarboxylic acid.
Sterling Drug Inc. European Patent Application, published Apr. 30, 1986 under No. 179,239, discloses 7-(2,6-dimethyl-4-pyridinyl)-1-ethyl-6-fluoro-1,4-dihydro-4-oxo-3-quinolin ecarboxylic acid.
Grohe et al. U.S. Pat. No. 4,670,444, issued June 2, 1987 (Bayer AG European Patent 78,362, published May 11, 1983) discloses 1-cyclopropyl-6-fluoro-7-(1-piperazinyl)-1,4-dihydro-4-oxo-3-quinolinecarb oxylic acid, also known under the generic name ciprofloxacin.
Gilligan et al. U.S. Pat. No. 4,636,506, issued Jan. 13, 1987, discloses compounds of the formula ##STR2## wherein R.sub.1 is hydrogen, a pharmaceutically acceptable cation or alkyl of 1 to 3 carbon atoms;
Y is selected from the group consisting of alkyl and haloalkyl of 1 to 3 carbon atoms, allyl, vinyl, cyclopropyl, hydroxyethyl, phenyl, 4-hydroxyphenyl and 4-fluorophenyl; PA1 R.sub.2 is 3-pyridyl or 4-pyridyl which may be substituted by one or two substituents selected from the group consisting of fluoro, chloro, hydroxy, alkoxy of 1 to 4 carbon atoms, amino, dialkylamino of 2 to 8 carbon atoms, hydroxyalkyl of 1 to 6 carbon atoms, aminoalkyl of 1 to 6 carbon atoms; 5-pyrimidyl, or 6-quinolyl, and PA1 R.sub.3 is fluoro; PA1 R' is selected from the group consisting of hydrogen, fluoro and --SR'", where R'" is phenyl, benzyl or lower-alkyl; PA1 R" is selected from the group consisting of hydrogen, fluoro and --SR'", with the proviso that when R" is hydrogen, R' is also hydrogen; PA1 Z is 3-pyridinyl or 4-pyridinyl substituted by from one to three lower-alkyl groups or an N-oxide thereof; or a group of the formula ##STR4## where R.degree. is acetoxy, hydroxy, chloro, amino, lower-alkylamino, di-lower-alkylamino or lower-alkoxy;
and the acid addition salts thereof when R.sub.1 is hydrogen. Example 1 of the patent discloses the preparation of 6,8-difluoro-1-ethyl-7-(4-pyridinyl)-4-oxo-3-quinolinecarboxylic acid.